1. Field of the Invention
This invention relates to a gate member for a resilient-seated gate valve, and more particularly, to a gate member with improved sealing to the valve body.
2. Description of the Prior Art
To improve sealing and reduce leakage through the valve when it is closed, gate valves have long used resilient material where the gate member mates with the valve body. Many patents show, and many manufacturers sell, gate valves with resilient material used in that way. See, for example, U.S. Pat. Nos. 2,420,849; 2,913,012; 2,942,841; 3,006,597; 3,151,838; 3,485,477; 3,633,873; 3,662,778; 3,738,383; 3,746,304; 4,162,058; and 4,223,868. In addition, the Clow Corporation markets a gate valve called the "R/W Valve" shown in the brochure "Resilient Wedge: A New Concept", A/S ESCO shows a gate valve in its flier "Sluseventil S-1100" and Daigle shows a gate valve in a brochure entitled "Vannes D-72--D'Avant-Garde", all of which have gate members that use resilient material on sealing surfaces.
Gate valves have various surfaces that must be completely sealed when the valve is closed. Gate valves have a valve body that forms a valve chamber having an opening. The gate member travels through the opening into and out of the valve chamber generally transverse to the direction of fluid flow through the valve. The opening into the valve chamber and the inside surfaces of the valve chamber contacted by the leading edge of the gate member must be sealed when the valve is closed.